Pituitary Gonadotropin-Releasing Hormone Binding Sites in Persistent Estrous Rats
作者:
Katalin Köves,
Bernard Kerdelhué,
Judith Molnár,
Valér Csernus,
Béla Halász,
期刊:
Neuroendocrinology
(Karger Available online 1988)
卷期:
Volume 48,
issue 5
页码: 489-494
ISSN:0028-3835
年代: 1988
DOI:10.1159/000125054
出版商: S. Karger AG
关键词: Pituitary;Gonadotropin-releasing hormone receptors;Persistent estrus;Estrous cycle;Hypothalamus
数据来源: Karger
摘要:
Pituitary gonadotropin-releasing hormone (GnRH) binding sites were studied in persistent estrous rats. For comparison females at different stages of the estrous cycle, ovariectomized animals, and intact males were examined. Persistent estrus was induced by a hypothalamic knife cut, administering testosterone to neonatal rats, or by constant illumination. Rats showing spontaneously such alteration were also used in the experiment. Besides pituitary GnRH-binding sites, the GnRH content of the median eminence and plasma luteinizing hormone, follicle-stimulating hormone, estradiol, and progesterone concentrations were determined. Pituitary GnRH receptors changed during the estrous cycle with the highest concentrations observed on proestrus. In rats in persistent estrus, pituitary GnRH-binding sites varied between proestrous and estrous values of cyclic females. Ovariectomy resulted in a significant increase in receptors. Depending on how the persistent estrous syndrome was induced, very different amounts of GnRH were found in the median eminence of the various groups. Our data indicate that the GnRH-binding sites on pituitary cells of persistent estrous rats are in essence not changed.
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